Similar to bladder outlet obstruction (BOO), overactive bladder (OAB) symptoms are very common and increase in prevalence as men age. Whether or not OAB symptoms are thought to be secondary to BOO, the goal of treatment of symptoms should result in an improved quality of life and ultimately prevent clinical deterioration. A common dilemma when treating men with obstruction and OAB is the risk of acute urinary retention or morbidities related to increasing postvoid residuals. In this article, the relationship of OAB to BOO is examined and the role of urodynamics and data on the use of anticholinergics in men with OAB and obstruction are reviewed. An algorithm for managing men with OAB also is proposed. In men with OAB without evidence of obstruction (including OAB after treatment for BOO), first-line medical therapy with anticholinergics is indicated. However, in men with OAB and concomitant BOO, nomogram has been developed to assist in the management of patients at risk for urinary retention. Men with significant obstruction should be appropriately treated to decrease bladder outlet resistance before adding anticholinergics for the treatment of OAB.